Flooding has been reported across portions of the Ohio River and Mid-Mississippi River Valleys as several inches of rain has fallen since the start of this week. At portions of the major rivers, including the Ohio River, the rivers are forecast to go into ‘major’ flood stage. Unfortunately, more rain is ahead through this weekend, which will allow for many rivers to rise and for more areas to experience flooding. There is potential for this flooding to be significant in certain areas. Some locations may endure over a foot of rainfall in total this week based on how much moisture is present in the atmosphere.
The forcing factors of this flood threat continues to be a strong ridge over the Southeast US and a ridge over the West. This is allowing for a funnel of highly anomalous, moist, tropical air to flow in all the way from the eastern Pacific Ocean. With this pattern locked in, it’s going to continue to rain for days. This will help aid in training showers and thunderstorms. With training storms, it’s when precipitation moves over the same areas with no eastward movement.
On Thursday, a light to moderate rain is forecast to fall across much of the interior Northeast into southern New England with showers in the Mid-Atlantic. We’ll also see a line of moderate to heavy showers and thunderstorms draped across the eastern Ohio Valley. However, much of this precipitation is expected to dissipate during the midday hours. To the south, a line of showers and thunderstorms is expected to span from the ArkLaTex through the Mid-Mississippi Valley. This line will also dissipate as the day progresses while it moves northeast. Meanwhile over the Southern Plains, a new storm system will be developing, leading to our next chance for heavy rain. Showers and thunderstorms will be prevalent across eastern Texas and Oklahoma and into the ArkLaTex regions throughout the day.
Then overnight Thursday, we’re thinking a line of heavy rain and thunderstorms will develop from the Great Lakes through the eastern Southern Plains. To be more specific, this line, which may contain rainfall rates of three inches per hour, will likely span from the Indianapolis area southwestward through Dallas. Some of these storms may contain strong, gusty winds, but we don’t think there will be any severe weather. This line of storms will very slowly move east, thus enhancing the the risk of flooding as they ‘train.’
As we get into Friday, we’ll continue to watch this line of heavy rain and storms. This line will stall out across the Mid-Mississippi Valley back into the ArkLaTex while it gradually diminishes across the Ohio and Tennessee River Valleys. In the Northeast, it will be bring rain and freezing rain to much of the region during the day. In regards to the weakening line of rain we just mentioned, there will likely still be showers around in the Ohio and Tennessee River Valleys, but it will be very light and will therefore not worsen the flood conditions. The Southern Plains and Mid-Mississippi will have a very different outcome. Moderate to heavy rain showers and thunderstorms are expected, especially in eastern Oklahoma and Texas, the Gulf Coast states (Louisiana and Mississippi), and Arkansas.
As yet another storm system moves in and strengthens, the rain will become more widespread and heavier in intensity. Rain and thunderstorms are forecast to fall across much of the Ohio, Tennessee, and Mid-Mississippi Valleys as well as the ArkLaTex region and parts of the Southern Plains while showers clear out of the Northeast from the previous storm system. If you haven’t noticed yet, day after day of rain continues to be forecast from the Mid-Mississippi Valley through the eastern Southern Plains. This is a big concern because of all this rain can lead to significant flooding.
Now on Saturday, the forecast turns quite interesting. Not only will there be heavy rain but there is a decent chance for severe weather from the ArkLaTex through the Mid-Mississippi Valley. Damaging wind gusts up to 70 mph and a few tornadoes seems like the greatest threats as of now. This severe weather risk may continue into Saturday night as well. Now in terms of the rain, it’s forecast to fall at times the Midwest, interior Northeast, Mid-Atlantic, Ohio and Mid-Mississippi Valleys, and eastern Southern Plains. The best chance for the heavy rain due to slow-moving, heavy thunderstorms will be co-located with the severe weather risk zone.
During Saturday night, a strong cold front will finally clear the rain out of the Southern Plains, although it will stall out along the Texas coast, keeping the rain in this area. That front will eventually clear all of the rain out of the region west of the Mississippi River by the time you wake up Sunday morning. Before then, heavy rain is forecast to fall across the Mid-Mississippi River Valley, then into the Ohio and Tennessee River Valleys. Rain will also span into the Northeast with even some freezing rain in northern New England and parts of the interior Northeast.
On Sunday, rain is expected up and down the East Coast of the United States with the exception of the Southeast and Florida coasts. Thankfully, the rain’s intensity will significantly decrease. Meanwhile along the Gulf Coast, the stalled front will remain on the wet side. The front will eventually clear the rain out of the Gulf Coast and Southeast by Monday night.